Abstract

Objective: High-field strength proton magnetic resonance spectroscopy (1H-MRS) and peripheral blood analyses reported in the literature reveal glutamate (Glu) and glutamine (Gln) abnormalities in schizophrenia. Given the relative ease and feasibility of using peripheral measures, the present study investigates the relation between peripheral and brain Glu and Gln levels.Methods: We recruited healthy volunteers (n = 17, mean age 21.9 [standard deviation 2.9, range 18–29] yr) between May and December 2005. All participants underwent 3 Tesla 1H-MRS analysis with segmentation (grey matter, white matter, cerebrospinal fluid) at the Nuclear Magnetic Resonance Centre at the University of Alberta Hospital to quantify medial prefrontal cortical (mPFC) Glu and Glx (i.e., combination of Glu and Gln). Within 1 week of 1H-MRS analysis, we collected plasma from the same participants for Glu and Gln quantification, using high-performance liquid chromatography at the Neurochemical Research Unit at the University of Alberta.Results: There was no correlation between plasma Glu and either medial prefrontal cortical Glu or Glx (R1,15 = 0.019, p = 0.944 and R1,15 = 0.081, p = 0.757, respectively). Similarly, there was no correlation between plasma Gln and either mPFC Glu or Glx (R1,15 = 0.029, p = 0.911 and R1,15 = 0.025, p = 0.925, respectively).Conclusions: Our findings support the use of 1H-MRS, instead of peripheral blood analysis, for investigating glutamatergic dysfunction in the brain.

Acknowledgements: This research was supported by the Bebensee Schizophrenia Research Foundation, University of Alberta Hospital Foundation, Canadian Institutes of Health Research, Alberta Heritage Foundation for Medical Research, Canada Research Chairs and Canada Foundation for Innovation programs, and the Natural Sciences and Engineering Research Council of Canada.

Contributors: Drs. Shulman, Baker and Tibbo designed the study. Drs. Shulman, Grant, Seres, Hanstock and Tibbo acquired the data; Drs. Shulman, Grant, Hanstock, Baker and Tibbo analyzed it. Drs. Shulman and Grant wrote the article; Drs. Seres, Hanstock, Baker and Tibbo critically reviewed it. All authors gave final approval for the article to be published.